Mineral oil composition



Patented st. 135, 1942 MINERAL OIL COMPOSITION Everett w. Fuller, Woodbnry, N. .L, assignor to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation or New York No Drawing. Application September 25, 1941, Serial No. 412,285

18 Claims.

This invention has to do with the stabilization of viscous mineral oil fractions against the deleterious effects of oxidation by the use of inhibitors of oxidation or, as more commonly designated,

oxidation-inhibitors" or anti-oxidants. More specifically, the present invention relates to the improvement or stabilization of such mineral oil iractions by the use of a novel class of reaction products, which when admixed with viscous mineral oils in minor proportions will prevent or retard undesirable changes taking place in the oils. To those familiar with theart it is well known that substantially all of the various mineral oil fractions are susceptible to oxidation. Such susceptibility to oxidation varies with the type and degree of refinement to which the oil has been subjected and with the conditions under which it is used or tested. Thus, the degree to which products oi oxidation are formed in an oil fraction is'a measure of the extent of removal of the various unstable constituents by refining operations and of the conditions of use of the oil fraction.

A highly refined viscous oil, for example, is one that has been refined by treatment with fuming sulfuric acid or with large quantities of concentrated sulfuric acid, or other means or combinations such as AlCh, solvents, and acids. When subjected to oxidizing conditions, such an oil tends to form relatively large amounts of acidic constituents. The presence of catalytic materials such as copper does not appear to affect appreciably the oxidation of highly refined oils, and such oils are less susceptible to the formation of colored bodies or of insoluble sludge. For most applications oi these oils, however, it is desirable that acidic bodies be absent, or that no increase in acidic bodies take place under conditions of use. Acidic bodies are corrosive to metals and therefore reduce the useful life of the oils as lubricants or for other purposes for which they come in contact with metals. Similarly, acidic bodies are injurious in textile lubricants and in spray oils. When the oils are used for insulation or cooling in electrical equipment such as transformers or capacitors, an increase in acidic bodies tends to lower the dielectric strength of the oil and has other undesirable harmful efi'ects. Oils that have been refined by treatment with only moderate amounts of sulfuric acid or other refining agents are designated as moderately refined oils. Such oils have a tendency to form relatively small amounts of acidic oxidation prodnote as compared with highly refined oils but depreciate in color and form substantial amounts of sludge. Metal catalysts such as copper materially accelerate deterioration of these oils. The principal objection to these oils is their tendency to deposit sludge, which interferes with heat-transfer in transformers and turbines and also causes plugging of oil teed lines in lubricating systems. Suflicient acid bodies may also be formed to cause reduction in the dielectric strength of these oils.

Solvent-refined oils are those which have been prepared by treatment with selective solvents such as chlorex, phenol, iurfural, etc. These oils are similar to moderately acid-refined oils in that metal catalysts such as copper accelerate their oxidation and in that such oxidation is concurrent with substantial color-depreciation and sludge-formation. In general, acid-formation is greater than with moderately acid-refined oils but much less than with highly refined oils. Sludgeand acid-formation lower their value for many purposes, such as those mentioned previously: electrical insulation, lubrication, etc. Solvent-refined oils have found extensive use as lubricants forinternal combustion engines because of their high viscosity index, but under the conditions of use encountered in crank cases such oils develop constituents which are corrosive toward certain metal bearings such as the cadmium-silver bearings, etc., which are sometimes used.

It is to be understood that the foregoing classification of oils as highly refined, moderately refined, and solvent-refined is not to be considered as in any way limiting the scope of this invention, for there can exist oils whose refining blending has been such as to make them intermediate in properties between the foregoing types. Briefly, response to inhibitors may be said to de-- pend entirely upon the type of oxidation and endproducts of oxidation of an oil, which in turn depends largely upon the degree of refining this oil has had. Further, the degree of refining required to produce these types of oils varies with the crude source so that any one refining procedure may produce either a highly refined oil or a moderately refined oil, depending upon the crude source. Pennsylvania type oils, for ex- Various types of compounds and reaction products have been proposed for use as stabilizers or oxidation-inhibitors for viscous mineral oil fractions. Apparently, the action of these inhibitors is catalytic,'and their development is therefore, influenced toa great extent by the o'xidi'zable constituents remaining in the all after a particular refining treatment. Certain inhibitors may be eifectivefto stabilizes mineral oil against sludge-formation and maybe ineflective upon acid-formation. Such inhibitors may re-' tard acid-formation inamoderately refined oil but may be totally in'eiiective in retarding acidformation in a highly refined oil. Thus,- the action, of most oxidation-inhibitors is selective,' and many such inhibitors are not comprehensive inaction so asto-stabilize a, mineral oil against all, of, the deleteriouseflects of oxidation.

. As. aforesaid; thisinlvention, has to; do with a novel class of reactionlproducts whichihas been found to be highly effective as stabilizers for viscous mineral oils refined by any of, the meth- )dSkl'lOWll tothe art and described; herein.

This invention ispredicated' upon the discovery ;hat the reaction products ofa dichlor alkyl ethervith a primary or secondary aromatic amine are iighly eflective inv small amounts as stabilizers If viscous mineral oils. The amines contemlated herein for reaction with the dichlor, alkyl :thers may. be representedrby thegeneral formula.

vherein B represents an aromatic hydrocarbon adical and R is selected from the group consistng of-hydrogen, aliphatic radicals, and aromatic adicals. It is to be understood that the term alkyl monoand poly-ethers with aromatic amines of the aforesaid type. By the term mono-ether is meant an ether characterized by one ethereal oxygen atom, such as Representative dichlor alkyl mono-ethers which may be used to form the typical reaction prodwherein R" represents an aliphatic radical.

Typical dichlor alkyl poly-ethers which may be used for the purposes of this invention are: dichlor triglycol; dichlor tetraglycol, etc.

As aforesaid, the reaction products contemplated herein are obtained by the reaction of a dichlor alkyl (monoor poly-) ether with a pri-- mary or secondary aromatic amine. The primary aromatic amines are characterized by the general formula.

wherein R. represents an aromatic hydrocarbon herein are represented by the general formula.

aromatic hydrocarbonvradical as, used herein inclusive of aromatic, hydrocarbon radicals R-m F .aving alkyl or aryl substituentsyalso, that the i,

arm "aliphatic radicals is inclusive of aliphatic adicals having aryl substituents.

More specific lly, the reaction products conemplated herein are those formed by reaction of ne moi equivalent of adichlor alkyl ether with t least two, and preferably four, mol equivalents I an aromatic amine of the aforesaid type. Such eaction products are much more eil'ective as iabilizers of viscousmineral oils than are those armed when a lower ratio of reactants is used. 1 some instances, as when equimolecular proporonsoi' an amine and etherv are used,reaction roducts characterized bya heterocyclic struclre are formed.- Certain reaction: products of 115, latter type are {not eii'ective stabilizers-as, m example, when equimolecular proportions of aniline, N -phenylaniline N-ethyl alpha-naphthylamine, N-phenyl alphanaphthylamine, etc.

45 wherein R represents an aromatic hydrocarbon radical and R is selected from the group consisting of aliphatic radicals and aromatic radicals N-phenyl+beta-naphthylamine,

The general method of preparation of these novel stabilizers consists of heating onemolecular proportion of the dichlor alkyl ether with at'least two, and preferably with at least four,

iiline and-beta, beta dichlor diethyl ether are ol c r proportions of the aromatic amine for d, some .pheny1 morpholjne is formed, Thi several hours, treating the mixture with alkali lmpoundhas been found to be of a lower degree o neutralize any amine hydrochloride formed. eflectiveness than reaction products ofthe d n Steam-distilling t to r ve 11m 3- me e ct t obtained by of at least w acted amine and ether. The residual oil is the ldprefembly four mql equivalents the aminev new stabilizer, which may or may not be further ,oneof, the ether. These reaction products are The following typical examples 111115 mansions-consistingapparently. ofmixtures'oi t in detail the Pl f Several of the c ntemplated reaction products: 7 V V W V V V V ntain some diaryl, amino-substituted alkyl tiers, their exact, composition, is uncertain. iey arethereforeidentiiied and defined herein reaction products. Typical reaction products contemplated by this rention are those formedby reaction of dichlor ExAMPLn Om:

Ethyl aniline-beta, beta dichlor diethyl ether reaction product:

96.8 grams (0.8 mol) of cthylaniline and 28.6 v ams (0.2 mol) of beta, beta dichlor diethyl ether were heated on a steam bath for 26 hours. The viscous liquid was treated with 200 cc. of a per cent solution of sodium hydroxide and steam-distilled to remove excess reactants. The residue was dissolved in benzene, filtered, solventdistilled oil, and the oil remaining was topped" to a pot temperature of 210 C. at 2 mm. pressure. The reaction product was a dark-colored viscous oil.

EXAMPLE Two Ethyl aniline-dichlor di-isopropyl ether reaction product:

96.8 grams (0.8 mol) of ethyl aniline and 3-1 grams (0.2 mol) of dichlor di-isopropyl ether were refluxed for 9 hours. The mixture was treated with 200 cc. of a 12.5 per cent solution of sodium hydroxide and steam-distilled to re-- move unreacted aniline and dichlor di-isopropyl ether. The residue was dissolved in benzene, filtered, dried, and the solvent evaporated off. The product was a viscousoil.

EXAMPLE THREE Anilz'ri e-dichlor triglycol (ClH4CzOCzH4OCgH4Cl) reaction product:

74.4 grams (0.8 mol) of aniline and 37.5 grams (0.2 mol) of dichlor diglycol were heated to approximately 200" C. for 8 hours. After the mixture was cooled, 200 cc. of a 12.5 per cent solution of sodium hydroxide were added thereto, and it was steam-distilled to remove unreacted aniline. The residue was taken up in benzene, washed with water, dried, and the solvent evaporated off. The reaction product was a viscous oil.

EXAMPLE Form Ethyl aniline-dichlor tetraglycol (ClH4C'zOCzH4OC'2H4OC'2H4C'Z) reaction product:

97 grams (approximately 0.8 mol) of ethylaniline and 46 grams (0.2 mol) of dichlor tetraglycol were reacted as given in"Example Three above. This gave an HCl-soluble viscous oil.

The following tests and results thereof illustrate the effectiveness of the class of reaction products and certain specific members within the class contemplated herein as antioxidants for viscous mineral oil fractions.

Tns'r No. I Oils highly refined with sulfuric acid The oil described below and blends thereof were subjected to the modified German tar test. Such a test involves heating a ISO-gram sample of the oil at a temperature of 120 C. while bubbling oxygen gas through the oil for a period of 70 hours. The acidic oxidation products formed were then determined by titrating with alcoholic potash. Results for the oil and for the oil blends containing typical reaction products contemplated herein are given in Table I below in terms of neutralization numbers (N. N.), such numbers representing the acidity of the 011 at the end of the test.

The oil used in this test was a highly refined oil suitable for use in transformers which had been prepared by treating a Coastal distillate with 40 pounds of 98 per cent sulfuric acid and 180 pounds, of 103 per cent oleum per barrel, followed by a. clay percolation. It had a specific In Table I below and in the following tables, the "addition agent is identified by the reactants used inpreparing the reaction product tested. For example, aniline-beta, beta dichlor diethyl ether indicates the product obtained by reacting these two compounds according to the procedure outlined above.

TEST No. 11

Oils moderately refined with sulfuric acid.

A mixed Mid-Continent and Coastal distillate had been refined by treatment with 70 pounds of 98 per cent sulfuric acid per barrel, neutralized,

washed, and percolated through clay. It had a specific gravity of 0.879, a flash point of 385 F., and a Saybolt Universal viscosity of 152 seconds at 100 F. It is an oil suitable for use in turbines.

gravity of 0.871, a flash point of 310 F., and

This oil and blends thereof containing typical reaction products of the type contemplated herein were tested as follows:

Twenty-five cc. samples of the oil (or the oil blend) were heated to 200 F. with 5 liters of air per hour bubbling through them. Twenty-four inches of No. 18 gauge copper wire and 1 gram of iron granules were addedto each sample. Also. 2 cc. of distiliedwater were added each day. The samples-were tested for acidity (N. N.) color, and sludge after varying periods of time. Results are given in Table II below.

TABLE II Sludge Per cent Time, Lov. Agent added used hours color g 168 0.99 2 17 None 240 2. 5 ll!) 24:; r 336 16.0 400 1,282 Aniline-beta, bets dichlor d ethyl ether... 0.10 g f arl st ain 0 P Y 167 0.01 2 40 572 2.8 75 133 Aniline-dlchlor (ll-isopropyl ether 0.10 9:53 Ethyl aniline-dichlor 161 0.01 1 5 di-isopropyl ether.--. 0. 10 497 0.0 2 16 1, 505 5.2 326 Aniline-dichlor trigly- 161 0 07 4 16 491 5. s 110 Ethyl aniline-dichlor tetmslycol 83 218 11% Tas'r No. III

Oils refined by means of solvents .The oil used in this test was a distillate from a Rodessa crude which had been refined with furfural, dewaxed, and filtered. The finished stock had a Saybolt Universal viscosity of 151 seconds at 100 F. This oil and blends thereof were tested by the method described in Test No. II above. The resultsare set forth in Table III below.

\ may cause their failure TABLE m I Sludge Percent Time Lov. Agent added used hours N color 92 o. 91 9 N 165 20.8 32o 25g Aniline-beta, beta 164 dichlor diethyl ether: 0. 0.08 1% 1(1): Ethyl aniline-beta, beta 8:8 1 13 dichlor diethyl ether: 0. 10 359 1 7 10 Aniiinedlchlor (ii-iso- 166 1 6 7 pro yl ether 0.10 503 1 3 Ethyi aniiinedichlor 161 01 1 2 di-isopropyl ether 0. 10 1 505 01 1 94 Ethyl aniline-dichlor 1 2 mglywl 10 497 0.4 4 8 Ethyl aniline-d ch or tetraglycol 0. 10 161 O. 9 6 25 'Izs'r N0. IV

' Corrosion test Motor oils, especially those refined by certain solvent-extraction methods, tend to oxidize when submitted to high temperature and to form products that are corrosive to metal bearings. This corrosive action may be quite severe with certain bearings, such as those having the corrosionsusceptibility of cadmium-silver alloys; and it short time. The following test was used to determine the corrosive action of a motor oil on an automobile connecting=rod bearing.

The oil used consisted of Pennsylvania neutral and residuum stocks separately refined by means of chlorex and then blended to give an S. A. E. 20 motor oil with a specific gravity of 0.872, a flash point of 435 F., and a Saybolt Universal viscosity of 318 seconds at 100 F. The oil was tested by adding a section of a bearing containing a cadmium-silver alloy surface and weighing about 6 grams and heating it to 175 C. for 22 hours while a stream of air was bubbled against the surface of the bearing. The loss in weight of the bearing during this I treatment measures the amount of corrosion that has taken place. A sample of the oil containing a stabilizer was run at the same time as a sample oi the straight oil, and the loss in weight of the bearing section in the inhibited oil could thus be compared directly with the loss of the section in the uninhibited oil. The results obtained in this test are setforth in Table IV below.

TABLE IV Mg. loss in weight 'Per cent d d Agentad'e m Inhibited nibited Aniline-beta, beta dichor diethyl ether 0.25 0 3i Ethyl aniline-dichlor di-isopropyl other 0.25 0 32 From the foregoing test results it will be observed that the reaction products contemplated herein are highly efi'ective to stabilizeviscous petroleum oil fractions against the normal deteriorating streets of oxidation as manifested by development of acidity, color and sludge, irreoxidation upon the oil may be varied depending upon the character of the oil and the severity of the conditions to which it is to be exposed, but in general it appears that the desired results may be obtained with an amount varying from 0.01 per cent to 1.00 per cent.

It is to be understood that while I have herein described in detail certain typical reaction procedures and several specific reactants which may be employed in synthesizing the reaction products contemplated herein, the invention is not confined to these specific procedural details or reactants but includes within its scope such changes and modifications as fairly come within the spirit of the appended claims.

I claim:

-1. An improved mineral oil composition com- 7 prising a viscous mineral oil fraction and in adwithin a comparatively 1 by reaction of one spective of the refining treatment which the oil a has received; and further that certain of these reaction products are highly eifective to retard the corrosive action encountered when certain oils are used in connection with normally corrosive alloy bearings. The quantity of reaction product used to inhibit the deleterious effects of 7s mixture therewith a minor proportion of a reaction product obtained by reaction of a dichlor alkyl ether and an aromatic amine represented by the general formula V wherein R represents an aromatic hydrocarbon radical and R is selected from the group consisting of hydrogen, aliphatic radicals and aromatic radicals, said product being present in an amount sumcient to inhibit the deleterious effects of oxidation upon the oil.

2. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether and at least two mol equivalents of an aromatic amine represented by the general formula sisting of hydrogen, aliphatic radicals and aromatic radicals, said product being present in an amount sufiicient to inhibit the deleterious effects of oxidation upon the oil.

3. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a reaction product obtained mol equivalent of a dichlor alkyl ether and at least two mol equivalents of an aromatic amine represented by the general formula RI wherein R represents an aromatic hydrocarbon radical, and R is selected from the group consisting of hydrogen, aliphatic radicals, and aromatic radicals, said product being present in an amount of irom about 0.01 per cent to about 1.00

per cent.

4. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction'product obtained by reaction of one mol equivalent of a dichlor alkyl monoether and at least two mol equivalents of an aromatic amine represented by the general formula wherein R represents an aromatic hydrocarbon radical and R is selected from the group consisting of hydrogen, aliphatic radicals, and aromatic radicals, said product being present in an amount suflicient to inhibit the deleterious efi'ects of oxidation upon the oil.

5. An improved mineral oil-composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction 01' one mol equivalent of beta, beta dichlor diethyl ether and at least two moi equivalents of an aromatic amine represented by the general formula wherein R represents an aromatic hydrocarbon radical and R is selected from the group consisting of hydrogen, aliphatic radicals, and aromatic radicals, said product being present in an amount sumcient to inhibit the deleterious efiects of oxidation upon the oil.

7. An improved mineral oil traction comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction of one mol equivalent of a dichlor trlglycol and at least two mol equivalents of an aromatic amine represented by the general formula wherein It represents an aromatic hydrocarbon radical and R is selected from the group consisting of hydrogen, aliphatic radicals, and aromatic radicals, said product being present in an amount suflicient to inhibit the deleterious eflects of oxidation upon the oil.

8. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether and at least two mol equivalents of a primary aromatic amine, said product being present in an amount suflicient to inhibit the deleterious efiects oi! oxidation upon the oil.

9. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion 01' a reaction product obtained by reaction-sot one mol equivalent of a dichlor alkyl ether and at least two mol equivalents of aniline, said product being present in an amount sufllcient to inhibit the deleterious effects of oxidation upon the oil. a

10. An improved mineral oil composition comprising a viscous mineral oil traction and in admixture therewith a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether and at least two mol equivalents of aniline,

said product being present in an amount of from about 0.01 per cent to about 1.0 per cent.

11. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether and at least two mol equivalents of a secondary aromatic amine, said product being present in an amount sufficient to inhibit the deleterious eilects oi oxidation upon the oil. a

12. An improved mineral oil'composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether and at least two mol equivalents of ethyl aniline, said product being present in an amount sufflcient to inhibit the deleterious effects of oxidation upon the oil.

alkyl ether and at least two mol equivalents or ethyl aniline, said product being present in an amount of from about 0.01 per cent to about 1.00 per cent.

14. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether selected from the group consisting of dichlor dimethyl ether; beta, beta dichlor diethyl ether; alpha, beta dichlor diethyl ether; gamma gamma dichlor dipropyl ether; beta, beta dichlor di-isopropyl ether; dichlor triglycol; and dichlor tetraglycol, and at least two mol equivalents oi! an aromatic amine represented by the general formula RN\R wherein R represents an aromatic hydrocarbon radical and R is selected from the group consisting of hydrogen, aliphatic radicals, and aromatic radicals, said product being present in an amount sufiicient to inhibit the deleterious effects of oxidation upon the oil.

15. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether selected from the group consisting of dichlor dimethyl ether; beta, beta dichlor diethyl ether; alpha, beta dichlor diethyl ether; gamma, gamma dichlor dipropyl ether;- beta, beta dichlor di-isopropyl ether; dichlor triglycol; and dichlor tetraglycol, and at least two mol equivalents of' a primary aromatic amine, said product being present in an amount sufficient to inhibit the deleterious effects of oxidation upon the oil, l

16. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether selected from chlor diethyl ether; gamma, gamma dichlor dipropyl ether; beta, beta dichlor di-isopropyl ether; dichlor triglycol; and dichlor tetraglycol, and at least two mol equivalents of aniline, said product being present in an amount sufficient to inhibit the deleterious effects 01' oxidation upon the oil. a

1'1. An improved mineral oil composition comprising a viscous mineral oil fraction and in admixture therewith a minor proportion of a reaction productvobtained by reaction of one mol equivalent of a dichlor alkyl ether selected from the group consisting of dichlor dimethylether; beta, beta dichlor diethyl ether; alpha, beta dichlor diethyl ether; gamma, gamma dichlor di= propyl ether; beta, beta dichlor di-isopropyl ether; dichlor triglycol; and dichlor tetraglycol; and at least two mol equivalents of a secondary aromatic amine, said product being present in an amount suincient to inhibit the deleterious eiiects otoxidation upon the oil.

18. -An improved mineral oil composition comprising a viscous mineral oil traction and in admixture therewith a minor proportion to! a reaction product obtained by reaction of one mol equivalent of a dichlor alkyl ether selected from the group consisting of dichlor dimethyl ether;v

beta, beta. dichlor diethyl ether; alpha, beta dichlor diethyl ether; gamma, gamma dichlor dipropyl ether; beta, beta dichlor di-isopropyl ether; dichlor trigylcol; and dichlor tetraglycol; and at least two mol equivalents of ethyl aniline, said product being present in an amount sufllcient to inhibit the deleterious etl'ects oi! oxidation upon the 011.

, EVERETT W, FULLER. 

